Earthmoving and construction type vehicles, which have endless self-laying track chain assemblies for support and propulsion, generally utilize a sprocket wheel to engage and drive the track chain. Several different types of sprocket wheels have been used in the past, including a single wheel member having a plurality of integral teeth, a circular support member for supporting wheel segments, each segment having several teeth, and hub members accommodating a plurality of separate individual teeth.
One type of drive sprocket having a plurality of separate, individual teeth bolted to a hub portion is disclosed in U.S. Pat. No. 2,365,544, issued to H. D. Geyer et al on Dec. 19, 1944. In this patent, the teeth are fulcrumed to the hub portion somewhere near the middle of the teeth so the teeth can rotate in either direction about the fulcrum. Resilient means are provided to return the teeth to their original no load position. This arrangement is intended to make the teeth self-adjusting to accommodate variations in the track chain.
Another type of sprocket having separate, individual teeth secured to a hub is shown in U.S. Pat. No. 3,996,814 issued to G. E. Westlake on Dec. 14, 1976. This patent discloses a plurality of link members secured together around the circumference of a hub. The links are keyed longitudinally and laterally on the hub. Each link carries one or more separate teeth projecting radially outwardly.
Still, another type of sprocket assembly with replaceable teeth is shown in U.S. Pat. No. 4,522,611, issued to D. M. Hiatt on July 11, 1985. This patent discloses a generally cylindrical sprocket hub equipped with a plurality of L-shaped pockets in the periphery of the hub. A replaceable tooth, having a partial T-shaped inner end, is intended to be received within each of the L-shaped pockets and locked in place by wedge lock means which operate against the T-shape of the tooth.
Each of the above-noted sprocket assemblies provide individual replaceable drive teeth. However, such sprocket assemblies appear to be quite complicated and costly and utilize intricately formed pieces. All of the above-noted patents would seem ineffective or quite limited in their ability to reduce noise levels during driving operation against an endless track chain assembly.
The present invention is directed to overcoming one or more of the problems as set forth above.